An experimental drug derived from marijuana that is currently being tested in clinical trials at a number of Texas hospitals has successfully treated epilepsy, its manufacturer announced Monday.

GW Pharmaceuticals saw its value double after the announcement. The drug, Epidiolex, is cannibidiol or CBD oil, and is taken orally. It does not contain the psychoactive chemical in marijuana, THC, that gets its users high. Texas Children’s in Houston participated in the FDA-approved clinical trial of Epidiolex, giving some patients the oil at different doses while administering others a placebo.

The successful trials were related to the treatment of Dravet syndrome, which can cause anywhere from a dozen to hundreds of seizures each day. It affects about one in 30,000 births.

Results from three other trials for similar conditions are expected later this year, including some from Fort Worth. Cook Children’s had 10 patients in its trial, which is testing the effectiveness of the drug in pediatric patients suffering from Lennox-Gastaut Syndrome, or LGS. Texas Monthly’s February issue included an in-depth feature on the trial at Cook’s. The magazine reported that patients with LGS could suffer up to 150 seizures a day. They’re severe, as well. One of the story’s subjects reported breaking her arm during a grand mal seizure.

According to Newsweek, the trial for Dravet syndrome logged a 39 percent median reduction rate in monthly convulsive seizures among those who were administered the actual drug. Those who took the placebo dropped by 13 percent. The trial included 120 patients, and the results caused GW’s shares to spike by 125 percent.

GW Pharmaceuticals will now meet with the Food and Drug Administration to determine a path to distribution. CBD oil is still classified as a Schedule 1 controlled substance, putting it in the same class as heroin and LSD.